Transportation officials have narrowed to two the number of possible routes for a superconducting maglev train line that would take passengers from Washington to Baltimore in 15 minutes — inching closer to reality a project that some dismiss as unrealistic.

With the pool of route alignments down to two, the Federal Railroad Administration, which is leading a federal review process, can move to select a preferred route and construction process. The federal government’s next step would be giving clearance for tunneling to begin as early as 2020 and operations in 2027.

That’s what project proponents are betting on, anyway. But upon completion of the environmental impact statement in mid-2019, the FRA could also rule against building the line — the wish of many residents along the route’s path.

Northeast Maglev, the team of private investors behind the project, touts the line as a way to ease travel along congested Interstate 95. Chiefly, the group says, it would add rail capacity to the Northeast Corridor — the nation’s busiest rail network — while the technology would revolutionize train travel, bringing it closer to flying and free it of the delays that plague today’s railroads.

“Our infrastructure is crying out for some kind of change,” Wayne Rogers, chief executive of Northeast Maglev, told a panel of Maryland lawmakers this month. Northeast Maglev’s sister company, Baltimore Washington Rapid Rail, would develop and operate the train.

The L0 series magnetic-levitation (maglev) train, undergoing testing by Central Japan Railway, at the Yamanashi Maglev Test Track in 2015. (Ko Sasaki for The Washington Post)

The 40-mile rail line is planned as the first leg of a system that would move people from Washington to New York in an hour. Building the D.C.-Baltimore stretch could cost between $10 billion and $12 billion, of which Northeast Maglev says it has secured $5 billion from Japan.

In recent months, the FRA eliminated about 10 routes that had been reviewed as part of the proposal. The eliminated routes would have had the most impact on communities, and some would have required the leveling of hundreds of homes. Most recently, they dropped a route that ran along the MARC system’s Penn Line, a ­heavily developed corridor.

The two remaining routes parallel the Baltimore-Washington Parkway. On the east side of the highway, the route would encroach on federal land, including the parkway, the National Security Agency at Fort Meade and NASA in Greenbelt. Northeast Maglev officials say this is their preferred option.

On the west side, the rail line would track along the edge of the Baltimore-Washington Parkway right of way and affect some residential properties.

About 75 percent of the route would run underground — 80 feet to 100 feet below, project officials say. Northeast Maglev estimates the project will create 74,000 construction jobs during the seven-year building period and 1,500 permanent positions once the system is operational.

Maryland transportation officials recently announced progress on the federal environmental review, stressing that the state isn’t funding the project but that it views it as vital to its economy.

“Our transportation system in place today in Maryland across the board is inadequate for the people that we have, and it is only going to get worse,” state Transportation Secretary Pete K. Rahn told a Maryland House committee this month. “That is why the administration has been open to the private sector bringing new ideas, new concepts to the state to try to solve some of these transportation dilemmas we have.”

The superconducting magnetic levitation train system, already operational in the testing phase in Japan, harnesses powerful magnetic forces that lift and propel trains four inches above a U-shaped guideway at up to 375 mph, much faster than Amtrak’s Acela Express trains, which run up to 135 mph.

The maglev isn’t the only high-speed travel concept Maryland is embracing. Last year, the state approved a conditional permit to Tesla founder Elon Musk’s tunneling start-up, the Boring Co., for the construction of several miles of tunnel for his high-speed Hyperloop system that will cart goods and people in vacuum-sealed tubes at high speeds. That decision was challenged by the Maryland Attorney General’s Office, which in a recent letter questioned the state’s authority to grant permission for tunneling beneath the Baltimore-Washington Parkway.

At a Feb. 6 hearing in Annapolis, Rahn defended the state’s decision, saying it gives access to its right of way for transportation services. The Washington Metropolitan Area Transit Authority, for example, has nine miles of its rail system beneath Maryland roadways, Rahn said. He said having the maglev and Hyperloop competing in Maryland show the state is at the forefront of new concepts in transportation.

Rahn said he anticipates another proposal for innovative transportation in the state to be announced this year, but he declined to elaborate.

“Maglev is a phenomenal technology. Is it the only technology? No. Is it the best technology? The marketplace is going to have to decide that,” said Rahn, who rode Japan’s 27-mile Yamanashi maglev line during a 2015 trade mission with Gov. Larry Hogan (R). “For us, we know that we have to be taking bold steps if we are going to ensure that we stay competitive for our economy and certainly if we want to try to maintain any quality of life.”

At municipal and state government hearings and in heated public meetings, elected leaders and residents who oppose the maglev have cited effects on private property and park land. They have also noted there are few to no benefits to the communities the train would go through. Some fear the project isn’t economically feasible and may result in existing rail services having to compete more for the few federal transportation dollars available.

“Why do we need to get from Baltimore to D.C. in 15 minutes?” Laurel City Council member Fred Smalls asked the Northeast Maglev team at a meeting on the project, one of several the city is holding.

“Why not?” said Kisha A. Brown, director of community and external affairs for the Northeast Maglev. “What are we missing out on by not allowing ourselves to think beyond our square mileage? . . . I think about the opportunities that we don’t have now, that we don’t even realize we have because we are not as connected.”

Smalls followed with questions about ridership, to which Brown said a study is underway to determine who would ride the train and whether there’s enough demand to make it economically feasible.

Smalls also asked about Maglev’s assertion that the project could boost property values. He noted the train would not stop in the communities between Baltimore and Washington. It has three planned stops: one in each city and at Baltimore-Washington International Marshall Airport.

“As the train travels in Prince George’s County, there’s no stops. I am trying to wrap my head around where the economic value for those areas come into play,” Smalls said.

Dennis Brady, a former Bowie City Council member who has organized a grass-roots group against the project, said a few hundred residents are planning a rally Monday in Annapolis to voice their concerns about the project’s economic feasibility and its impact on private property and park land.

“The overwhelming opinion of the people is this isn’t good for our region,” Brady said. “We want to bring the message that we don’t believe this is a viable proposal and that it should be blocked.”